14 lines
443 B
Forth
14 lines
443 B
Forth
: ackermann ( m n -- u )
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over ( case statement)
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0 over = if drop nip 1+ else
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1 over = if drop nip 2 + else
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2 over = if drop nip 2* 3 + else
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3 over = if drop swap 5 + swap lshift 3 - else
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drop swap 1- swap dup
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if
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1- over 1+ swap recurse recurse exit
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else
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1+ recurse exit \ allow tail recursion
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then
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then then then then
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;
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